Laundry apparatus



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United States Patent Office Patented Sept. 15., 1964 3,148,523 LAUNDRY APPARATUS Leonard I. Kownurko, Holland, and Richard H. Brill, Philadelphia, Pa., assignors to Philco Corporation, Philadelphia, Pa., a corporation of Delaware Filed Feb. 7, 1962, Ser. No. 171,769 1 Claim. (Cl. (S8-12) This invention relates to compact tumble action laundry apparatus and more particularly to an improved means for operating such apparatus.

The term compact as used in the specification and claims designates a washer, or washer-dryer, in which the clearance between the tub and drum has been reduced to such an extent that there exists a water-chasing problem.

As the technology of automatic washing advances, there is an increasing demand for more compact machines. Achievement of this end, while still retaining the same i load-washing capacity, results in a severe reduction in the clearance between the stationary tub and the rotatable clothes drum and under certain conditions of operation considered hereinafter, gives rise to the problem known as water chasing. This phenomenon results when the rotating drum dips into the pool of liquid at the bottom of the stationary tub causing the retained water to tend to follow the rotating drum. The water, which is literally chased into the cavity separating the tub and drum, acts hydraulically to couple the rotating drum to the fixed tub producing a severe power drain on the drive system. The result of this drag is to increase the power requirements of the motor needed to drive the rotating drum at a given speed, or to achieve the desired terminal velocity in a given time given a desired acceleration rate. As the clearance between tub and drum diminishes, this problem becomes increasingly acute necessitating the use of larger more powerful motors. When the hydraulic coupling exists, the motor stays on the start windings for a greater period of time resulting in overheating and consequent intermittent operation due to actuation of associated protective switching. The problem is particularly acute during the initial phase of each extraction run at which time the rate at which water is centrifuged from the material exceeds the rate at which it can be pumped The result is an accumulation of water in the bottom of the tub producing a severe waterchasing problem.

As suggested above, the dominant causes of water chasing, apart from the principal cause of reduced clearance between drum and tub, are the increasing rotational speeds used to effect water extraction and the further fact that the water pump in conventional washers is directly driven by the drive motor. The first of these causes results in chasing of the liquid up into the space separating the stationary tub and rotating drum, and in keeping the extracted uids suspended within the interfacial cavity defined by the tub-drum surfaces. The second of these causes contributes to the formation of a liquid pool in the bottom of the tub during the initial accelerating phase of the extraction run for the reason that the unit drive motor is placed Linder a severe load as the drive transmission is shifted into high speed operation. This results in reducing the speed of the drive motor, during this transient period, to a fraction of its rated synchronous speed which is reflected in loss of pump output.

One partial solutionto this problem is to divorce the pump drive from the transmission drive motor so that loading of the motor will have no effect on the speed with which the pump is driven. Another solution is to interpose between the drive mechanism and driven tub some type of torque limiting device. This latter approach effectively isolates the drive motor from the load, permitting the motor to operate at substantially synchronous speed regardless of load conditions. These approaches, however, offer only a partial solution to the problem and are both expensive and space consuming.

It isan object of this invention to provide an inexpensive means for solving the problem of water chasing.

It is a further and more particularized object of this invention to provide means for operating compact tumble action washers, during the extraction phases of the wash cycle, which substantially eliminates water chasing and its attendant problems.

Another and still more detailed object of this invention is to provide a novel combination of extractionspeed sequences which eliminates both water chasing and clothes-sticking normally resulting from high speed extraction in compact machines.

These, and other objects and features of the present invention will be apparent from a consideration of the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a sectionalized front elevational view of a compact, washer-dryer combination machine embodying the present invention;

FIGURE 2 is a sectional View of a two speed gear transmission of a kind usable in machines of the type shown in FIGURE l;

FIGURE 3 shows a timer sequence chart designed to illustrate the method teachings of this invention;

FIGURE 4 is a schematic wiring diagram embodying one form of control system designed to produce operation in accordance with the method teachings of this invention;

FIGURE 4A is a diagrammatic representation of a subinterval sequence of operations designed to eliminate water chasing in a machine of the type illustrated; and

FIGURE 4B is a chart outlining the switching operations effected by use of push button controls, the specific mechanism for its accomplishment is of conventional construction and has not been shown.

In achievement of the foregoing, as well as other objectives, a preferred embodiment of the present invention contemplates provision, in compact tumble action washers of the class in which the rotatable clothes drum and water pump are directly connected to a multispeed transmission, of a unique sequence of operations phased t0 occur immediately prior to the initial stages of extraction and comprised of a plurality of intermittent extraction pulses or runs of sub-interval duration spaced by interim periods during which the drum is returned to tumble speed operation to permit discharge of previously extracted water. The interim between pulsed extractions allows ther pump to come up t0 full operating speed and effectively to discharge the accumulated water. By this sequence of actions water is removed periodically after each incremental extraction run. The time intervals are so chosen as to attain a satisfactory extraction speed without excessive overload of the motor followed by a time interval sutiicient to permit pump-out of substantially all extracted water. By breaking down a single time interval into a series of subinterval extraction runs spaced by interim periods of pump-out, i.e., by employment of the subinterval spincycle above described, the problem of water chasing is completely eliminated. It is of particular signilicance that this complex problem has been eliminated by the novel employment of an additional cam and a pair of switch contacts.

The characterization used in the specification and in the claim, that the clothes drum .and pump are connected directly to the drive means is significant in defining the field of this invention, since shifting of the transmission 3 from low to high speed operation results in loading of the drive motor with an attendant reduction in motor speed. This occurs, for example, during the initial stages of extraction and has a direct and corresponding effect on pump operation.

Referring to FIGURE 1 the invention is depicted, for exemplary purposes, as being embodied in laundry equipment of the washer-dryer, tumble action type. It should be understood that while the aforementioned apparatus embodies, in a single unit, both a washer and a dryer, the present invention is equally as well adapted for use in a washer alone.

The machine chosen for illustration includes a cabinet structure in which a drum and tub assembly 11 is suspended by means of springs 12 and shock absorbers 13 in a manner set forth in U.S. Patent 2,642,996, to Oeler et al. issued June 23, 1943, and assigned to the assignee of the present invention. The tub assembly 11 comprises a perforated cylindrical drum 14 adapted to rotate about a substantially horizontal axis within a cylindrical liquidretaining tub 15. To insure tumbling of the clothes within the drum during its rotation the drum is provided with inwardly presented, V-shaped vanes or ribs 16. A stub shaft 17 is affixed to the rear wall 20 of the drum 14 and extends axially thereof through a bearing (not shown) housed in the rear wall structure of the tub 15. A pulley 21 is carried on the outer end of shaft 17 and is driven, by belt 18, through a two-speed transmission by the synchronous motor 22.

For the washing and rinsing phases of operation, water is introduced into tub by conventional means not shown, the water being withdrawn from the tub by means of an impeller type, solenoid actuated drain pump 23 driven by motor 22. This pump communicates with sump 24, provided in the lower part of tub 15, by means of a flexible hose 25. A lint trap 26 is removably positioned below the discharge opening of the sump to permit removal of accumulated lint and sediment. Drainage of the water from the drum is controlled by means of solenoid 27 which actuates a valve located in the inlet port of the water pump.

For the drying cycle, the machine is provided with an electrical resistance heater 30 disposed within a recessed portion 31 of the drum enclosure 15. Means for cooling the circulated air may include a water-vapor condenser, not shown, disposed within the enclosure in the region of embossed portion 32 located opposite the heater 30.

As is well known in the art, drum 14 is rotated at a low tumble speed during the washing operation and at a higher speed during the water-extraction phases of the cycle. During the drying operation clothes are tumbled at the lower speed uniformly to expose the fabrics or clothes being dried to circulating heated air to facilitate drying.

Referring to FIGURE 2 of the drawing, the transmission 33, forming part of the driving connection between the motor 22 and drum pulley 21, is capable, per se, of producing, selectively, a lower or a higher drum speed when driven by a constant speed motor. The illustrated motor is of a conventional type having formed integrally therewith a housing 34 and an armature shaft 35 extending outwardly from the motor and serving as the transmission drive shaft. The transmission is also of conventional type and is disposed within an open ended housing 36 adjacent the end of the motor housing 34, said end together with the housing 36 serving completely to enclose the transmission 33. A pinion 40 is formed integrally with armature shaft 35 and drivably meshes with the teeth of the large gear 41, the latter being loosely sleeved on the driven countershaft 42 journalled within the transmission housing 36. Countershaft 42 is parallel to motor armature shaft 35 and is provided on its outwardly projecting end with a drive pulley 45.

A clutch member 46 is mounted upon armature shaft for rotation therewith, and has attached thereto conical clutch shoes 47. These shoes are arranged for seating in a correspondingly shaped recess in a second clutch member 50 loosely sleeved at the end of armature shaft 35. This second clutch member 50 is provided with teeth 51 that mesh with a gear 52 mounted on the countershaft 42 for rotation with the latter. The arrangement is such that low speed drive is through pinion and gear 41, and high speed drive is through gears 51 and 52.

The gears 41 and 52 are arranged along the countershaft 42 and are releasably connected to one another by means of a one-way drive connection in the form ofa suitably arranged helical spring clutch 54 anchored to gear 41 by pin 55, and which tends to tighten about the respective shoulder portions 56 and 57 of the gears 41 and 52, when driven in one direction, and which tends to loosen and unwind from the shoulders when driven in the opposite direction.

When there is no pressure on clutch members 46 and 50, they separate slightly axially and lower speed drive occurs from the opinion 40 through the gear 41 clutched by spring 54 'to gear 52 which latter member is keyed to the countershaft 42. Gear 51 turns freely under this condition of operation.

To initiate high speed operation solenoid 60, shown in FIGURE 2, is energized, causing its armature 61 to move toward the left, as viewed in FIGURE 2. This action applies axial pressure through link 62 to thrust shaft 63 driving the gear-clutch member towards clutch member 46 thereby effecting engagement of the clutch members and causing the armature shaft 40 to drive the clutch gear 51. This rotates the countershaft 42 at high speed directly through the gear 52. During this phase of operation the low speed gear 41 rides idly on the countershaft.

Operation of the above transmission in performance of the various machine functions proceeds in accordance with the schedule oulined in the timer sequence chart shown in FIGURE 3. The switching arrangements which are productive of the various modes of operation are shown in FIGURE 4B. The wiring diagram shown in FIGURE 4, except for those portions discussed in detail hereinafter, is of conventional construction and will not be elaborated upon except insofar as its operation affects the present invention. Details of the conventional aspects of operation can be determined by reference to FIGURES 3, 4, 4A and 4B.

In the illustrated machine the clearance between the tub and the 21" diameter drum is on the order of about one half inch, the drum being powered by a nominally rated Va horsepower motor. The drum is operated through the intermediation of the above described two speed transmission, at a tumble speed of r.p.m. and an extraction speed of 650 r.p.m. As indicated previously, on initiation of the extraction phase, there is normally produced, in machines of the type above described, a condition which results in severe water-chasing.

In avoidance of this problem and in accordance with the invention, there is impressed on the interval of operation immediately preceding each extraction phase a sequence of operations consisting, in the preferred form, of a plurality of subinterval-duration extractions spaced by interim periods of tumble speed operation, during which time the water extracted during the immediately precedmg extraction run is discharged. The aggregate effect of this action is cumulatively to discharge sufficient water from the machine to prevent water-chasing on establishment of high speed extraction. The sequence of steps in acorrtlishment of this end is initiated by closure of contact Referring to FIGURE 4, it will be seen that energization of this contact, through cam detiection of the timeroperated blade 64, places the subinterval control switch 65 'in series circuit with the high speed spin solenoid symbohcally represented in the circuit diagram by resistance 1 60. This places the increment of timer operation immediately preceding each extraction phase under control of the subinterval switch. To synchronize the operation of this switch with the closure of contact 9B and to integrate this action with the balance of the timer operated cycle, the cam 66 which controls operation of switch 65, is constructed as an integral part of the timer drive cam 67 which latter cam controls operation of the timing function of timer 68. The timer and its drive motor are diagrammatically illustrated to the right in FIGURE 4 to facilitate explanation, the timer motor TM actually being physically located in the main circuit between the points designated A'-B. By this technique each incremental advance of timer 68, produced by 360 rotation of cam 67, produces an integrated sequence of operations of switch 65 predetermined by the profile cut into cam 66. As will be seen by reference to the wiring diagram (FIG- URE 4) switch 65 isv inffectual in controlling operation of spin solenoid 60 until closure of the series-connected switch 9B. In the illustrated embodiment the cam 66 is provided with a succession of depressions 70 each of increasingly greater arcuate length designed to effect closure of movable contact 1'1 with fixed contact 72 in accordance with a desired subinterval operation sequence. One operational arrangement is shown graphically in FIGURE 4A.

The subinterval cycle of operations which is established through the coordinate action of switch 65 and contact 9B, controls operation of the transmission-shifting solenoid 60 and consists of three intermittent subintervalduration extraction runs, each of increasing duration spaced by interim periods during which water extracted during the immediately preceding extraction run is discharged. The sequence begins with a five second extension of the timer-controlled function immediately preceding extraction, in order to compensate for cam tolerances. This insures proper introduction of the special operational sequence which, in the illustrated embodiment, officially begins with a first extraction run of five seconds duration. Under average load conditions, a l H P. split-phase induction motor acting through a two speed transmission geared to produce an extraction speed of 650 r.p.m., will normally only attain a speed of about 200-300 r.p.m. during this first five second extraction run. The terminal velocity after 5 seconds of spin will of course vary in accordance with the size of the load. During this spin period, a certain amount of water extraction will occur, the operational sequence in this instance being custom designed for full load conditions using the machine described.

To prevent hydraulic coupling between the tub and drum, only a limited amount of water is centrifuged at any one time and at a spin velocity substantially below full spin speed. Immediately following each limited period of extraction the drum is returned to tumbling speed for ten seconds. During this time the motor will attain full speed and will drive a directly connected, or belt-connected pump, at its fully rated capacity so as to remove substantially all the water which has been extracted during the immediately preceding extraction run. A succeeding extraction run of ten seconds duration will extract another portion of the absorbed water, which in turn will be prevented from interfering with the rotating drum by a ten second return to tumble speed and pump out. This is followed by a second period of extraction during which a still greater portion of the remaining water is removed. The subinterval spin cycle is terminated by running the drum for five seconds at tumble speed in order to discharge the balance of the water. The unit is then returned to normal timer operation by ,opening of Contact 9B, and closure of contact 3T, establishing the normal high speed extraction run through energization of the high speed spin solenoid 60. The sequence of events just described occurs during the interval immediately preceding each extraction or spin phase, or what 6 might be considered the first interval of each spin phase as indicated in the chart of FIGURE 3 reading vertically.

In the machine illustrated there is an additional refinement of operation which occurs just prior to the extraction preceding the drying phase of the composite washerdryer cycle. This refinement is identified as the interruptor operation and preferably occurs during the 44th and 45th intervals of timer-controlled operation. Details of this portion of the cycle, which precedes the final spin phase, are disclosed and claimed in U.S. Patent 2,760,639 to J. J. Haverstock. The interruptor operation is designed to prevent the objectionable adherence of the materials being treated, to the wall of the clothes drum following high speed extraction, a condition referred to in the trade as Plastering Briefly described the procedure consists of first flushing out a major portion of the rinsing liquid from the material at a speed intermediate the tumble and extraction speeds; allowing the material to break away from the cylinder by slowing or stopping the rotation thereof; and then spinning out the remaining excess liquid at high speed; the material within the drum gravitates away from the inside wall as the centrifugal force exerted on said materials falls to a point below the gravitational pull. Breaking away of the materials from the surface of the cylinder at all times is thereby assured, since at no time are they again subjected to the flushing action of large quantities of liquid at high rotative speeds and the sticking action which attends such operation. Means for achieving the required intermediate speed spin necessary to the accomplishment of the above objective and without resort to a costly three speed transmission, are fully disclosed in the copending application of James R. Hubbard Serial No. 172,345, `filed February 9, 1962, which case is a divisional application of the Hubbard et al. application Serial No. 779,351, now Patent No. 3,100,- 387, filed December 10, 1958, and assigned to the assignee of the present invention. One technique, schematically shown in FIGURE 4 and of which there are several, is to interpose in series connection with the motor circuit 22a, centrifugal switch means 75. The switch in this ernbodiment is physically connected to the countershaft 42 of motor 22, inboard of pulley 45 as graphically shown in FIGURE 2, and is accordingly responsive to variations in the transmission output speed. As will be seen by reference to FIGURES 3 and 4, the interruptor switch 75 is in parallel circuit with motor energizing contact 7B and is only effective in cycling power to motor 22 when the shunting effect of line 76 is removed by opening of contact 7B. The clothes drum is driven at its tumble, or lower, speed by maintaining timer contacts 9B and 3T open and closing contact 7B. The closing of contact 7B acts electrically to remove centrifugal switch from the circuit.

Intermediate centrifuging speed, needed to prevent clothes-sticking is initiated by opening contact 7B at the beginning of the interruptor function and closing contact 5B. The cam which controls operation of contact 5B is configured to effect closure of the contact several increments before initiation of the interruptor operation in order to compensate for cam tolerances. This switch, however, as noted above, is not effectual until contact 7B is opened, at which time the input to motor 22 is solely through the centrifugal switch 75. Opening of contact 7B is followed by the subinterval sequence of operations shown in FIGURE 4A. Energization of spin solenoid 60 on closure of switch 65 acts to shift transmission from its 32 to 1 ratio to a speed ratio of 2.66 to l. As a result of this loss of mechanical advantage the motor will decelerate from a speed of approximately 1740 r.p.m. to a speed of less than 650 r.p.m. As is seen by referring to FIGURE 4, the centrifugal switch 75 is of the tiyball governor type, the bellcrank arms 76 being pivoted at 77 so that on movement of the balls 78 in an outward radial direction the translatable carriage 80, mounted for axial movement along countershaft 42 (FIGURE 2) is withdrawn from the movable contact 81, against the bias of springs 79, breaking its connection with the fixed contact 82. By this arrangement, as the motor attempts to come up to speed, the centtrifugal switch interrupts the power at some predetermined speed level providing for cyclic energization and deenergization of the motor 22 in response to predetermined rotational speeds of the latter. In the illustrated embodiment, the switch 75 is designed to close at approximately 600 r.p.m. and to open at about 700 r.p.m. It will be understood that the operational limits and the switch control range are merely design features to be empirically determined for the particular machine involved. The effect of this arrangement is to drive the drum 14 at a speed intermediate the lower and higher speeds provided by transmission 33.

To prevent water-chasing during this critical phase of operation there is superposed on the interruptor portion of the cycle, the subinterval sequence of operations previously described. This results in limiting the terminal speed which is attained during the interruptor sequence of operations to the maximum intermediate speed imposed on the system by the centrifugal switch 75.

The interruptor circuit, as pointed out in detail in the above identified application, and as indicated briefly above, is designed to provide a simplified means utilizing a two speed transmission, to achieve an intermediate rotational speed designed to eliminate the problem of clothes plastering.

This procedure is normally only resorted to during the period immediately preceding nal extraction in order to insure adequate distribution of the clothes during the drying cycle. Articles are prevented from sticking by resorting to a sequence of steps the first of which consists of extracting a major portion of the liquid retained by the clothes after the wash phase by rotating the drum at a centrifuging speed intermediate the tumbling and extraction speeds. The drum rotational speed is then reduced below the first centrifuging speed to a point suicient to permit the materials to gravitate away from the wall of the drum followed by increasing the speed of the drum to the final extraction speed. By superposing on this operational sequence the subinterval cycle of operations previously described the desired quantityrof water which is necessary to be extracted from the clothes in order to prevent clothes sticking is accomplished by a sequence of short time duration extractions in lieu of a single inter mediate speed centrifuging run thereby preventing waterchasing while at the same time fully realizing the advantages inherent in the Interruptor cycle of operation which latter mode of operation prevents clothes plasterin g.

Although the invention has been described with particular reference to specific practice and embodiments, it will be understood by those skilled in the art that the apparatus of the invention may be changed and modified without materially affecting the method teachings of the invention as defined in the appended claim.

We claim:

In compact laundry apparatus of the class which is timer driven through a sequence of intervals in performance of laundering operations, which apparatus comprises a rotatable basket and drive means operatively associated therewith including a gear transmission shiftable to provide low speed rotation of said basket in performance of washing and rinsing operations, and a higher rotational speed for water extraction, and to which transmission said basket yand a pump mechanism are directly connected, the improvement which comprises: means for intermittently shifting said transmission into high speed operation for subinterval periods of time immediately preceding an extraction run to provide partial extraction of water from articles being washed; means providing for spacing of said intermittent periods of extraction by interim subinterval periods during which said transmission is shifted into low speed operation to permit discharge by said pump mechanism of water extracted in an immediately preceding subinterval extraction run whereby cumulatively to effect withdrawal of suflicient water from the apparatus to prevent water-chasing on establishment of normal extraction, arid means operative in response to rotational speeds of said drive means, when said transmission has been shifted to provide said subinterval periods of extraction, cyclically to modulate the operational speed of said drive means to provide an effective rotational speed of said basket intermediate said lower and said higher speeds provided by said transmission.

References cited in the me of this paient UNITED STATES PATENTS 2,760,639 Haverstock Aug. 28, 1956 2,875,526 Engel et al Mar. 3, 1959 2,981,089 Neyhouse et al Apr. 25, 1961 3,056,203 Toma Sept. 25, 1962 FOREIGN PATENTS 829,292 Great Britain Mar. 2, 1960 

